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(11) | EP 1 061 627 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Electrical ground fault protection circuit |
| (57) The electrical ground fault protection circuit (10) includes power and ground LINE
connections (12) that are connectable to power (18a, 18b, 18c) and ground lines of
an electrical distribution system. They also include power and ground LOAD connections
(14) that are connectable to a load (29). Power and ground paths extend from the power
and ground LINE connections to the power and ground LOAD connections and include an
interrupter (72) having a connect position in which it allows current flow from the
LINE connections to the LOAD connections and a disconnect position in which it interrupts
such current flow. A ground line monitor (64) detects the presence or absence of a
fault condition in the ground line (20). In response to the presence of a fault condition,
the circuit switches the interrupter from its connect position to its disconnect position.
The power path monitor (66) detects the presence or absence of a fault condition in
the power path (18a, 18b, 18c). In response to the presence of a fault condition in
the power path, the circuit switches the interrupter from its connect to its disconnect
position. The circuit (10) includes a ground path and plural power paths extending
from the power and ground LINE connections to the power and ground LOAD connections
(18a, 18b, 18c). A voltage monitor (VM12, VM21, VM3) is interconnected between each power path and the ground path (20). The monitors
detect the presence or absence of a voltage drop in the power path. In response to
the presence of a voltage drop of a predetermined amount, the circuit switches the
interrupter from its connect position to its disconnect position. |